The 17-year-old jumped from the third-floor balcony of his Killara home on Wednesday, and police believe he had taken either the synthetic substance 25B-NBOMe or 25I-NBOMe, which was allegedly sold to him as LSD.

His father Stephen Kwan says moments before he jumped he told his mother and sister he wanted to fly.

"They tried to save him from jumping but they couldn't help because they are not strong enough," Mr Kwan said.

He says Henry was a good boy who studied hard and wanted to become a lawyer.

Mr Kwan says the drugs should not be available online and he wants the NSW Government to ban their sale.

"All parents should be aware of this synthetic drug, because it can be available everywhere easily, so the Government really needs to do something to try and stop this," Mr Kwan said.

While such a ban must be introduced at a state level, Federal Health Minister Tanya Plibersek says the Federal Government would support it.

"I think it is extremely worrying that people are taking these substances, just buying them off the internet, rolling the dice and putting these things in their bodies," Ms Plibersek said.

"It is extraordinary really the type of risks these people are taking."

Drug and Alcohol Research Training Australia director Paul Dillon says the use of synthetic drugs, which are marketed as mimicking the effects of illicit drugs, is on the rise because they are cheap and readily available online.

"They're seen as relatively benign and they can't be detected by drug dogs, so they're becoming very attractive - they're also incredibly cheap," Mr Dillon said.

But Mr Dillon warns that users have no way of knowing what they are taking or its effects.

"The problem is that some of this LSD does not contain LSD - it's containing some pretty nasty substances, substances that have caused deaths in Europe," he said.

"Certainly the emergency room presentations across Sydney and across the country that we've recently associated with LSD we believe is linked to this drug."

An 18-year-old man has been charged with supplying a prohibited substance to Henry Kwan and will face court next month.